Background: Thyroid disorders may have a negative impact on the prognosis of patients
affected by chronic heart failure (CHF).
Objective: The aim of the current study was to evaluate the prognostic role of all thyroid disorders over
a long term follow-up in a single centre large sample of CHF outpatients.
Methods: In all patients, the function of the thyroid was evaluated at the enrolment and during the follow-
up. On the basis of free triiodothyronine (T3), free thyroxine (fT4) and thyroid-stimulating hormone
(TSH) serum levels, patients were classified into one of the following four categories: euthyroid
subjects, patients affected by hypothyroidism, low T3 (LT3) syndrome and hyperthyroidism. During the
follow-up, death for all causes was assessed as primary end-point, whereas time to the first hospitalization
for heart failure worsening was the secondary end-point analyzed.
Results: Among 762 patients, 190 patients were affected by hypothyroidism (Hypo). LT3 syndrome
was diagnosed in 15 patients and 59 patients were affected by hyperthyroidism (Hyper). During a long
term follow-up (5.1±3.7 years), 303 patients died. Patients with Hypo showed an increased risk of death
as well as of hospitalization due to heart failure worsening at univariate regression analysis. At multivariate
regression analysis, Hypo remained associated with hospitalization after correction for age >75
years, ischemic aetiology, diabetes, therapy with ACE-inhibitors or ARBs, therapy with betablockers
and with aldosterone antagonists, NYHA class 3, systolic arterial pressure <95 mmHg, left ventricular
ejection fraction <30%, estimated glomerular filtration rate <60 ml/min, hyponatremia and NTproBNP>
1000 pg/ml. At multivariate analysis, the independent association with death was significant
only for the subgroup of patients with TSH >10 mIU/L. LT3 was independently associated with both
heart failure hospitalization and death, whereas Hyper was not associated with any of the two considered
Conclusion: Hypo is associated with a worse prognosis over a long-term follow-up. The association
with heart failure hospitalization is not dependent on the baseline TSH levels, whereas the association
with death is significant only when TSH >10 mIU/L. Finally, Hyper does not have any association with
a worse prognosis.